Graphics- and multimedia-enabled computer systems and full-featured content authoring environments facilitate the creation and publication of documents that can contain non-textual objects. Non-textual objects include graphics, icons, pictures, sounds, and other forms of visual, audible, and tactile content and can be provided in lieu of or to complement text.
Non-textual objects, however, cannot be processed by assistive technologies, such as used by individuals with physical or cognitive difficulties or impairments. Assistive technologies are generally designed to process text only. Other widely-used technologies are also unable to process non-textual objects, such as non-graphical, text-only Web browsers, graphical Web browsers configured to not render non-textual objects, popular search engines, and numerous character-based legacy applications. In situations in which a non-textual object cannot be accessed or processed, alternate content for the non-textual object can serve as a substitute for the non-textual object. For example, assistive technologies present alternate text in place of a graphical image for visually impaired persons.
In the United States, recent amendments to the Rehabilitation Act of 1973 require individuals with disabilities who are federal employees or members of the public to have access to and use of information and data in a manner comparable to access and use by individuals without disabilities. This requirement has been interpreted to embrace information presented by Web-based applications, on-line content, and similar forms of stored data, including the provisioning of alternate content for non-textual objects. Additionally, the Web Content Accessibility Guidelines, published by the Worldwide Web Consortium, recommend always providing textual alternatives for non-textual objects.
To not distort the meaning of a document, alternate content for non-textual objects should be composed in the context of the content that is proximate to the non-textual objects. For example, if a non-textual object is located in the middle of a sentence, assistive technologies or text-only applications will “read,” that is, substitute, the alternate content for that non-textual object as if the alternate content were part of the sentence. Alternate content should be composed in-context to ensure that such substitutions, as well as other uses of alternate content, remain consistent with the meaning of the document and surrounding proximate content. Though content authoring environments generally offer composition features that can accommodate generating alternate content for non-textual objects, these environments present alternate content in isolation and out of context. For example, the input areas for alternate content in Microsoft Word, licensed by Microsoft Corporation, Redmond, Wash., and Dreamweaver, licensed by Macromedia, San Francisco, Calif., do not present content that is proximate to the non-textual object in the document. Authoring correct and appropriate alternate content is therefore difficult when alternate content is displaced from proximate content.
Proximate content is determined relative to the physical placement of a non-textual object in a document. Nevertheless, authoring environments are oriented towards only the logical view of a document. This limitation presents challenges to correcting and authoring appropriate alternate content when formatting is applied to non-textual objects, as the physical and logical placements of a non-textual object can differ. For instance, the logical placement of a floating image, that is, where text wraps around an image, is generally not the same as the physical image placement.
Authoring tools also restrict the compositional features available for editing alternate content. Extended features, such as spell checking, grammar checking, search, replace and thesaurus access, are unavailable when composing and editing alternate content.
Therefore, there is a need for an approach to supplement content authoring environments with an intuitive interface for flexibly composing, in-context, alternate content for non-textual objects. Preferably, such an approach would present alternate content contextually co-located with the content, such as textual content, that is located proximate to the physical placement of the non-textual objects and accommodate multiple authoring environment layout schemes.